The present invention generally relates to cases for disc-shaped recording mediums, and more particularly to a case for a disc-shaped recording medium comprising a jacket for accommodating a disc-shaped recording medium and a closing member for closing an opening of the jacket and having a construction in which the jacket and the closing member engage with each other, which operates together with a disc-shaped recording medium reproducing apparatus having releasing means for releasing the engagement between the jacket and the closing member and is constructed so that the closing member is positively prevented from displacing with the releasing means.
Conventionally, cases accommodating a disc-shaped recording medium (hereinafter simply referred to as a disc) such as a video disc recorded with video signals, and an audio disc recorded with pulse code modulated (PCM) audio signals, have been proposed. In this type of disc cases, a disc remains at a predetermined position within a reproducing apparatus by performing an operation in which a disc case having the disc accommodated therein is inserted within the reproducing apparatus and then pulled out from the reproducing apparatus, and by inserting the empty disc case into the reproducing apparatus, the disc within the reproducing apparatus is incased inside the disc case, to be obtained outside the reproducing apparatus.
The above conventional type of a disc case comprises a rigid jacket for accommodating a disc, and a tray having a front part which is held by holding means upon complete insertion of the disc case within the reproducing apparatus and an annular or ring portion fixed to the front part for encircling the outer periphery of the disc. Furthermore, an engaging mechanism was provided for engaging the tray and the jacket so that the tray does not slip out from the jacket, in a state where the tray is inserted within the jacket. When this disc case is inserted within the reproducing apparatus to a predetermined position, an engagement releasing mechanism releases the engagement of the above engaging mechanism, and the holding means of the reproducing apparatus holds the tray. Hence, when the jacket is pulled out from within the reproducing apparatus, the disc is held by the annular portion of the tray and relatively slipped out from the jacket at the above predetermined position, and the outer peripheral edge part of the disc rests on and is supported by a supporting mechanism within the reproducing apparatus. Then, a turntable relatively rises within the inner side of the supporting mechanism, and the disc is placed onto and is unitarily rotated with the turntable, to perform the reproduction. After completion of the reproduction, when the empty jacket is inserted into the reproducing apparatus, the disc is relatively inserted into the jacket together with the annular portion of the tray, and the holding operation of the holding means is released. Accordingly, when the jacket is pulled out from the reproducing apparatus, the disc and the tray is obtained outside the reproducing apparatus together with the jacket in a state in which the disc and the tray is incased inside the jacket.
Thus, in the above conventional disc case, the peripheral side surface of the disc is held by the engaged annular portion of the tray and the disc remains within the reproducing apparatus upon pulling of the jacket outside the reproducing apparatus. Accordingly, a supporting mechanism which is placed with the remaining disc thereon and supports the outer peripheral edge part of the disc, is provided in the reproducing apparatus. Hence, the turntable must be constructed so as to relatively move up-and-down within the inner side of the supporting mechanism. This means that the diameter of the turntable must be smaller than the diameter of the disc, and the outer peripheral edge part of the turntable thus makes contact with and supports the disc at the signal recording surface which is to the inner side of the outer peripheral edge part of the lower disc surface. Therefore, scratches are easily made on the signal recording surface part of the disc which is supported by the turntable, and especially when starting the rotation of the turntable, suffers a disadvantage in that scratches are more easily made in this case due to a force acting in a direction so as to rub the disc. Accordingly, when the disc is used many times, fine reproduction cannot be obtained due to the above scratches formed on the signal recording surface of the disc. Furthermore, the above tray comprises the annular portion for encircling the outer peripheral surface of the disc, and thus suffers disadvantages in that the construction of the disc case is complex, the manufacturing of the disc case is troublesome, and the disc case requires a large amount of material and cannot be manufactured at low cost. Moreover, upon reproduction, when a reproducing transducer of the reproducing apparatus moves to the position of the signal recording surface on the disc surface, the reproducing transducer must traverse over the annular portion of the tray. This traversing movement accordingly leads to a disadvantage in that the reproducing transducer moving mechanism must be designed so that the reproducing transducer does not collide with the annular portion, and the construction of the mechanism thus becomes complex. In addition, the conventional disc case suffered a disadvantage in that, when the disc is relatively pulled out from the jacket by the tray upon insertion and then pulling out of the jacket from within the reproducing apparatus, or when the disc is relatively inserted into the jacket by the tray upon insertion of the empty jacket and then pulling out of the jacket, the jacket rubs against the disc and scratches are easily introduced. Thus, in order to eliminate the disadvantageous features of the conventional case, a novel case was proposed in U.S. patent application Ser. No. 229,303 entitled "CASE FOR A DISC-SHAPED RECORDING MEDIUM" filed Jan. 28, 1981, and now issued as U.S. Pat. No. 4,360,845, in which the assignee is the same as that of the present application.
A case for a recording medium operates together with recording medium reproducing apparatus provided with an inserting opening through which the case is inserted, a lid plate engagement releasing member, a lid plate holding member, and a disc clamping member provided at the innermost part of the recording medium reproducing apparatus opposite to the inserting opening with respect to a turntable which rotates the disc, and a jacket opening enlarging member provided in the vicinity of the inserting opening, capable of moving between the position in the vicinity of the inserting opening and the innermost part of the recording medium reproducing apparatus above the turntable. The case comprises a jacket having a space for accommodating the disc and an opening for allowing the disc to go in and out of the jacket, and a lid plate inserted through the opening of the jacket for closing the opening of the jacket, and further has a mechanism for engaging the lid plate and the jacket. Upon insertion of the case into the reproducing apparatus through the inserting opening, the engagement of the lid plate with respect to the jacket is released by the engagement releasing member, and the opening of the jacket is enlarged by the jacket opening enlarging member within the cutouts of the lid plate. The lid plate is held by the holding member. When the jacket is inserted into the innermost part of the reproducing apparatus, the clamping member enter from the enlarged opening of the jacket, to clamp the disc within the jacket. The jacket is pulled out in an empty state leaving behind the lid plate held by the lid plate holding member and the disc clamped by the disc clamping member, when the jacket is pulled out from within the reproducing apparatus in a direction opposite to the direction of the insertion.
In both the conventional and the proposed case for a disc-shaped recording medium, the tray or the lid plate is constructed to engage with the jacket. Accordingly, as the case is inserted into the innermost part of the reproducing apparatus, the case is constructed so that the case relatively makes contact with an engagement releasing member provided at the innermost part of the reproducing apparatus, to release the above engagement.
However, in both the above cases for a disc-shaped recording medium, the engaging member of the tray or the lid plate and the engagement releasing member of the reproducing apparatus respectively have vertical surfaces with respect to the horizontal plane, and these members were constructed so that the engagement releasing member relatively made contact with the engaging member to push and displace the engaging member within the horizontal plane. In a state where the empty jacket is pulled out from the reproducing apparatus leaving behind the tray or the lid plate and the disc inside the reproducing apparatus, the tray or the lid plate is clamped or held by the clamping member or the holding member.
In a state where the above tray or the lid plate is clamped or held, the above engagement releasing member only makes contact with the engaging member in a direction within the horizontal plane. Therefore, when a shock is exerted against the reproducing apparatus from the outside, the engaging member deviates in the vertical direction with respect to the engagement releasing member, and the tray or the lid plate is inclined. In extreme cases, the engaging member separated from the engagement releasing member. When the engaging member is displaced from the correct position with respect to the engagement releasing member as described above, the recovering operation to recover the disc and the tray or the lid plate within the jacket cannot be performed positively, since the tray or the lid plate is sometimes not relatively inserted smoothly into the jacket, or the jacket is sometimes not inserted into the predetermined position due to contact between the jacket and the engagement releasing member, upon insertion of the empty jacket inside the reproducing apparatus to recover the disc and the tray or the lid plate within the reproducing apparatus.